Alternative reproductive tactics in male freshwater fish influence the accuracy of species recognition

Sexual conflict can result in coercive mating. Because males bear low costs of heterospecific mating, coercive males may engage in misdirected mating attempts toward heterospecific females. In contrast, sexual selection through consensual mate choice can cause mate recognition cues among species to diverge, leading to more accurate species recognition. Some species show both coercive mating and mate choice–associated courtship behaviors as male alternative reproductive tactics. We hypothesized that

if the selection pressures on each tactic differ, then the accuracy of species recognition would also change depending on the mating tactic adopted. We tested this hypothesis in the guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis) by a series of choice experiments. Poecilia reticulata and G. affinis males both showed imperfect species recognition and directed all components of mating behavior towards heterospecific females. They tended to direct courtship displays more frequently towards conspecific than heterospecific females. With male P. reticulata, however, accurate species recognition disappeared when they attempted coercive copulation: they directed coercions more frequently towards heterospecific females. We also found that heterospecific sexual interaction had little effect on the fecundity of gravid females, which suggests that pre-pregnancy interactions likely underpin the exclusion of G. affinis by P. reticulata in our region.

Methods
exp1_maleMateChoice ------ exp1_maleMateChoiceDataset.csv (2019/07/23): Male association preference for con- and heterospecific females.

                       |-- exp1_1_summaryResult.R: Average, Standard deviation, and paired t test for male association preference.

                       |-- exp1_2_dirichletReg.R: Effect of body size estimated using Dirichlet regression

exp2_matingBehavior ------ maleIDandBehavior.csv (2019/05/04): Frequency of mating behaviors for con- and heterospecific females

                       |-- 2_1_behaviorFreqeuncy_overdispersion.R: Overdispersion test for each behavior (Table S1)

                       |-- 2_2_Fig2_behaviorFreqeuncy.R: Boxplot for each behavior

                       |-- 2_3_testEachBehavior.R: Wald tests for differences in behavioral frequency between male and female combinations

                       |-- FigS4_behaviorTransitionNetwork.R: Illustrate the behavior transition network

exp3_fecundity ------ exp3_fecundityDataset.csv (2019/01/18): Male effect on female fecundity

                  |-- 3_1_fecundityExperimentSummary.R: Summary of experiment (Table S2) 

                  |-- 3_1_fecundityExperimentSummary.R: Estimation of size-fecundity relationship using Poisson regression